Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method for estimating a transfer function at a central office (CO) to be used for performing loop qualification of a digital subscriber line between the CO, and a customer premises (CP) regardless of the topology of the loop to be qualified, the method comprising the steps of: retrieving at the CO a value Z in1 0 of the impedance at the CO side when the end of the line at the CP is short circuited, retrieving at the CO a value Z in1 0 of the impedance at the CO when the end of the line at the CP is open and estimating, using a calculator, the transfer function based on a transmission matrix T expressed by the following equation: T = [ Z in 1 ∞ f s 2 Z in 1 ∞ - Z in 1 0 Z in 1 ∞ Z in 1 0 2 ( Z in 1 ∞ - Z in 1 0 ) f s 2 f s 2 Z in 1 ∞ ( Z in 1 ∞ - Z in 1 0 ) Z in 1 ∞ ( Z in 1 ∞ - Z in 1 0 ) f s 2 ] wherein f S is set to 1 under the assumption that an impedance of the ports of the loop are equal to each other such that the loop to be qualified is assumed to be symmetric independently of the symmetric characteristics of the loop to be qualified.
A method for estimating the transfer function of a DSL (Digital Subscriber Line) loop at the central office (CO) to assess loop quality regardless of the loop's physical layout. This involves measuring the line's impedance from the CO under two conditions: when the customer premises (CP) end is short-circuited (Zin10) and when it's open-circuited (Zin1∞). A calculator then uses these impedance values to compute the transfer function based on a transmission matrix (T). The matrix calculation simplifies by assuming the loop is symmetric (impedance at both ends are equal), setting a factor 'fs' to 1. This symmetry assumption allows estimation of the transfer function even if the actual loop is not perfectly symmetric. The transfer function is calculated using: T = [ Zin1∞ * fs / (2 * (Zin1∞ - Zin10)), (Zin1∞ - Zin10) / (Zin1∞ * Zin10) * fs /2; fs/2 * Zin1∞ / (Zin1∞ - Zin10), Zin1∞ / (Zin1∞ - Zin10) * fs /2 ] where fs = 1.
2. The method according to claim 1 , wherein the retrieved value of the impedance at the CO side, when the end of the line at the CP is short circuited, is retrieved by means of a single-ended line testing (SELT) based method.
The DSL loop transfer function estimation method as described previously, where the impedance measurement at the central office (CO) with a short circuit at the customer premises (CP) end (Zin10) is obtained using a single-ended line testing (SELT) method. SELT is a technique where measurements are taken from only one end of the line (the CO in this case) to determine line characteristics. Therefore, the method from the previous description explicitly uses a single-ended testing approach for acquiring the short-circuited impedance value needed for the transfer function calculation.
3. The method according to claim 1 , wherein the retrieved value of the impedance at the CO side, when the end of the line at the CP is open, is retrieved by means of a single-ended line testing (SELT) based method.
The DSL loop transfer function estimation method as described previously, where the impedance measurement at the central office (CO) with an open circuit at the customer premises (CP) end (Zin1∞) is obtained using a single-ended line testing (SELT) method. SELT is a technique where measurements are taken from only one end of the line (the CO in this case) to determine line characteristics. Therefore, the method from the previous description explicitly uses a single-ended testing approach for acquiring the open-circuited impedance value needed for the transfer function calculation.
4. An arrangement for estimating a transfer function at a central office to be used for performing loop qualification of a digital subscriber line between the central office (CO) and a customer premises (CP) regardless of the topology of the loop to be qualified, the arrangement comprising: retrieving means for retrieving at the CO a value Z in1 0 of the impedance at the CO side when the end of the line at the CP is short circuited, retrieving means for retrieving at the CO a value Z in1 ∞ of the impedance at the CO when the end of the line at the CP is open and a calculator for estimating the transfer function based on a transmission matrix T expressed by the following equation: T = [ Z in 1 ∞ f s 2 Z in 1 ∞ - Z in 1 0 Z in 1 ∞ Z in 1 0 2 ( Z in 1 ∞ - Z in 1 0 ) f s 2 f s 2 Z in 1 ∞ ( Z in 1 ∞ - Z in 1 0 ) Z in 1 ∞ ( Z in 1 ∞ - Z in 1 0 ) f s 2 ] wherein f S is set to 1 under the assumption that an impedance of the ports of the loop are equal to each other such that the loop to be qualified is assumed to be symmetric independently of the symmetric characteristics of the loop to be qualified.
An arrangement for estimating the transfer function of a DSL (Digital Subscriber Line) loop at the central office (CO) to assess loop quality regardless of the loop's physical layout. This setup includes: means for measuring the line's impedance from the CO when the customer premises (CP) end is short-circuited (Zin10), means for measuring the line's impedance from the CO when the CP end is open-circuited (Zin1∞), and a calculator. The calculator then uses these impedance values to compute the transfer function based on a transmission matrix (T). The matrix calculation simplifies by assuming the loop is symmetric (impedance at both ends are equal), setting a factor 'fs' to 1. This symmetry assumption allows estimation of the transfer function even if the actual loop is not perfectly symmetric. The transfer function is calculated using: T = [ Zin1∞ * fs / (2 * (Zin1∞ - Zin10)), (Zin1∞ - Zin10) / (Zin1∞ * Zin10) * fs /2; fs/2 * Zin1∞ / (Zin1∞ - Zin10), Zin1∞ / (Zin1∞ - Zin10) * fs /2 ] where fs = 1.
5. The arrangement according to claim 4 , wherein the retrieved value of the impedance at the CO side, when the end of the line at the CP is short circuited, is retrieved by means of a single-ended line testing (SELT) based method.
The arrangement for DSL loop transfer function estimation, as described previously, where the impedance measurement at the central office (CO) with a short circuit at the customer premises (CP) end (Zin10) is obtained using a single-ended line testing (SELT) method. SELT is a technique where measurements are taken from only one end of the line (the CO in this case) to determine line characteristics. Therefore, the arrangement from the previous description explicitly uses a single-ended testing approach for acquiring the short-circuited impedance value needed for the transfer function calculation.
6. The arrangement according to claim 4 wherein the retrieved value of the impedance at the CO side when the end of the line at the CP is open is retrieved by means of a single-ended line testing (SELT) based method.
The arrangement for DSL loop transfer function estimation, as described previously, where the impedance measurement at the central office (CO) with an open circuit at the customer premises (CP) end (Zin1∞) is obtained using a single-ended line testing (SELT) method. SELT is a technique where measurements are taken from only one end of the line (the CO in this case) to determine line characteristics. Therefore, the arrangement from the previous description explicitly uses a single-ended testing approach for acquiring the open-circuited impedance value needed for the transfer function calculation.
7. The arrangement according to claim 4 further comprising a controller for controlling an arrangement at the CP side for automatically changing the load impedance at the CP side.
The arrangement for DSL loop transfer function estimation as previously described, further including a controller at the central office (CO). This controller manages an arrangement located at the customer premises (CP) which automatically switches the load impedance connected to the DSL line at the CP end. This allows the system to remotely control and set the load impedance at the CP, facilitating different impedance measurements needed for loop qualification. The CP arrangement could use relays or electronic switches to select different load resistors.
8. The arrangement according to claim 4 further comprising a controller for controlling an arrangement at the CP side for arranging an open line and a short circuited line.
The arrangement for DSL loop transfer function estimation as previously described, further including a controller at the central office (CO) which manages an arrangement at the customer premises (CP). This CP-side arrangement is capable of creating both an open circuit and a short circuit at the CP end of the DSL line. The CO-side controller remotely commands the CP arrangement to switch between these two states (open and short). This automated switching enables the system to remotely configure the line for the necessary impedance measurements required for calculating the transfer function and assessing the loop's quality.
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August 5, 2014
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